Any vessel that is under orders to fly a flag at half-mast would raise the flag to the peak at morning colors, then lower it to the half-mast elevation until evening when the flag would be again raised to the peak, then lowered and removed from the halyard.
Nick

QUOTE : "Which U.S. Military vessel lowers its flag in the morning and raises it the evening?" (Emphasis Added)

I think Nick (NAVA1974) pretty much hit the nail on the head when he wrote (QUOTE) : "Any vessel that is under orders to fly a flag at half-mast would raise the flag to the peak at morning colors, then lower it to the half-mast elevation until evening when the flag would be again raised to the peak, then lowered and removed from the halyard." (Emphasis Added)

About the only thing that I would add would be to suggest that Nick's observation would probably apply ONLY to those U.S. Military vessels that were "at anchor" and/or "in port". I use the qualifier "probably", because I don't know for sure IF any such "half-staff" order would apply to U.S. Military vessels that were "underway" (ie. "at sea").